Objectives: As COVID-19 will not be the last pandemic, understanding our historical response allows us to predict and improve our current practices in preparation for the next pandemic. Following the removal of the elective surgery suspension at the onset of the COVID-19 pandemic, it is unclear whether sports medicine surgery volume has returned to pre-pandemic levels as well as whether the BACKLOG from the original suspension was addressed. The purpose of this study to observe the monthly changes in volume and BACKLOG of knee and shoulder sports surgery one year since the original suspension. Methods: National all-payer data was utilized to identify patients undergoing knee and shoulder sports procedures from January 2017 to April 2021. Descriptive analysis was utilized to report the monthly changes in surgeries. A linear forecast analysis using historical data was utilized to determine the expected volume. This was compared to the observed case volume. The difference in expected and observed volume was utilized to calculate the estimated change in BACKLOG. Results: From March to May 2020, there was a persistent decrease in the observed shoulder and knee sports volume when compared to the expected volume. By June 2020, all knee and shoulder sports volume reached the expected volume. By April 2021, the estimated BACKLOG for shoulder and knee procedures had increased by 49. 8% (26, 412 total cases) and 19. 0% (26, 412 total cases), respectively, with respect to the original calculated BACKLOG from March to May 2020. Conclusion: Within four months, the sudden decrease in volume for knee and shoulder sports procedures had returned to pre-pandemic levels,however, the original BACKLOG in cases has continually increased one year following the suspension. Additionally, the BACKLOG is significantly higher for knee when compared to shoulder surgeries. Level of evidence: IV

Demand is assumed constant in the classical economic order quantity (EOQ) model.However, in the real world, the demand is dependent on many factors such as the selling price, warranty of product and marketing effort. In addition pricing and ordering quantity decisions are interdependent for a seller when demand for the product is price sensitive in the inventory models. These types of models are very popular in the literature as joint pricing and order quantity models. Many researchers consider these models under some conditions such as quantity discount, trade credit and marketing effort. In this paper, we propose a new inventory model for the seller who conducts marketing effort. The marketing effort is the process of performing market research, selling products and/or services to customers and promoting them via advertising to further enhance sales. It is used to identify the customer, to satisfy the customer, and to keep the customer. This process will happen during the planning horizon; therefore the product will be demanded increasingly as time passes. This increasing in the demand leads to the backorder condition in the model. Since the marketing effort as a decision variable is dependent of the time, in this paper, the marketing effort is assumed a linear function of time which has an effect on the demand in addition of price in our model. The model would be included the backorder cost due to raising the shortage of inventory in addition, the purchasing, ordering and holding costs. An algorithm for finding the optimal solution for the selling price, marketing expenditure and the time length of positive stock are obtained when the seller’s profit is maximized. To clarify the model more, numerical examples presented in this paper, including sensitivity analysis of some key parameter- the cost parameters and non-cost parameters- that will compare the obtained results of proposed model.

While there has been overall progress in addressing the lack of access to surgical care worldwide, untreated surgical conditions in developing countries remain an underprioritized issue. Significant BACKLOGs of advanced surgical disease called neglected surgical diseases (NSDs) result from massive disparities in access to quality surgical care. We aim to discuss a framework for a public health rights-based initiative designed to prevent and eliminate the BACKLOG of NSDs in developing countries. We defined NSDs and set forth six criteria that focused on the applicability and practicality of implementing a program designed to eradicate the BACKLOG of six target NSDs from the list of 44 Disease Control Priorities 3rd edition (DCP3) surgical interventions. The human rights-based approach (HRBA) was used to clarify NSDs role within global health. Literature reviews were conducted to ascertain the global disease burden, estimated global BACKLOG, average cost per treatment, disability-adjusted life-years (DALYs) averted from the treatment, return on investment, and potential gain and economic impact of the NSDs identified. Six index NSDs were identified, including neglected cleft lips and palate, clubfoot, cataracts, hernias and hydroceles, injuries, and obstetric fistula. Global definitions were proposed as a starting point towards the prevention and elimination of the BACKLOG of NSDs. Defining a subset of neglected surgical conditions that illustrates society’, s role and responsibility in addressing them provides a framework through the HRBA lens for its eventual eradication.

Background  During COVID-19 healthcare systems had to make concessions to make room for the surge of COVID-19 patients requiring hospital and intensive care. Postponing surgeries was a common strategy; however, it is unclear how surgical care was delivered during this time of constraint. The objective of this study was to understand how surgical care was delivered and prioritized during the COVID-19 pandemic response. Methods  This was an environmental scan following the Canadian Agency for Drugs and Technologies in Health methodology. This study was conducted in Canada; a universal, publicly funded healthcare system. Evidence sources on policies pertaining to the provision of surgical care between January 2020 and October 2022 were obtained from ministries of health, health services agencies and publicly funded hospitals across all 10 provinces and three territories. We synthesized the evidence sources using framework analysis. Results  We identified 205 evidence sources that described six themes about the provision of surgical care during the COVID-19 pandemic: the cycle of postponement and resumption; guidelines for triaging and prioritizing surgical cases; Infection Prevention and Control (IPAC), and safety measures for surgical care during COVID-19, patient-centred care, and looking forward (recovery planning, leadership, and decision-making). Conclusion  This study provides a comprehensive understanding of how surgical care was disrupted and innovated during COVID-19 which can inform future strategies for providing effective and efficient surgical care during times of healthcare constraint.

It is important to share demand information among the members in supply chains. In recent years, production and inventory systems with advance demand information (ADI) have been discussed, where advance demand information means the information of demand which the decision maker obtains before the corresponding actual demand arrives. Appropriate production and inventory control using demand information leads to the decrease of inventory and BACKLOG costs. For a single stage system, the optimal base stock and release lead time have been discussed in the literature. In practical production systems the manufacturing system has multiple processes. The multiple stage production and inventory system with ADI, however, has been analyzed by simulation or assuming exponential processing time. That is, their theoretical analysis and optimization of release lead time and base stock level have little been obtained because of its difficulty. In this paper, theoretical analysis of a two-stage production inventory system with advance demand information is developed, where the processing time is assumed deterministic and identical; demand arrival process is Poisson, and an order base stock policy is adopted. Using the analytical results, optimal release lead time and optimal base stock levels for minimizing the average cost on the holding and BACKLOG costs are explicitly derived.

Supplier selection is the process by which firms identify, evaluate, and contract with suppliers. The supplier selection process deploys a tremendous amount of a firm's financial resources. Nowadays, supplying the required resource of organizations has become an important business approach so a competitive advantage may be gained by the selection of the best suppliers to provide products/services more effectively and efficiently. Many models have been developed for solving supplier selection problem. In this paper, in addition to considering the incremental discount strategies, cost of shortages is also considered so far has not been considered. In this model, two objective functions of cost minimization of the buyer, and maximize quality of product is considered. To solve the proposed supplier selection model, an improved harmony search algorithm is used. The results show that the proposed algorithm works properly in the term of both CPU time and the quality of solutions. Finally, some numerical examples for model analyses are presented.

Kanban control systems used to optimize inventory levels just in time (JIT) production systems. Evaluation of kanban systems are based on flow control principles and it plays a very important role in production systems. This article presents a new dynamic card control methodology in order to keep a high level of performance measures. The main advantage of the proposed method is easy to adjust parameters. A simulation model for generalized kanban control system with dynamic adjustment of kanban size is proposed. Simulation experiments designed to test the effect of kanban sizes on performance measures such as total production time and amount of work in process، as well. The results of the simulation model indicate the improvement in production rate and reduction of BACKLOG demand by automatic and dynamic adjustment of kanban size.

The purpose of this paper is to present a polynomial time algorithm which determines the lot sizes for purchase component in Material Requirement Planning (MRP) environments with deterministic time-phased demand with zero lead time. In this model, BACKLOG is not permitted, the unit purchasing price is based on the all-units discount system and resale of the excess units is possible at the ordering time. The properties of an optimal order policy are argued and on the basis of them, a branch and bound algorithm is presented to construct an optimal sequence of order policies. In the proposed B&B algorithm, some useful fathoming rules have been proven to make the algorithm very efficient. By defining a rooted tree graph, it has been shown that the worst-case time complexity function of the presented algorithm is polynomial. Finally, some test problems which are randomly generated in various environments are solved to show the efficiency of the algorithm.